In this post, we will report results and draw conclusions for our study of soil contamination in the Tintic Mining District. This study was supported by a grant from the American Chemical Society.

Students from Walden School of Liberal Arts brought back 42 samples of soils from the area in and around Eureka, Utah. Our purpose was to test for heavy metal contamination, especially lead. Previous tests done by the Utah Department of Health and the EPA showed lead contamination to be widespread throughout the town, due to the presence of historic concentration plants in the town and the use of mine waste rock as fill in many lots. Since there are mine dumps on the hillsides south of town, rain runoff also brought lead contamination into the residential areas.

Western side of the Swansea Consolidated mine dump near SIlver City.

These tests led the EPA to declare the town a Superfund project and spend $26 million to replace soils in some areas of town (but not all). They also placed limestone riprap over the mine dumps to prevent further runoff. The process took ten years and completely changed the look of the town, damaging or destroying several historic landmarks along the way, such as the headframes for the Eureka Hill and Gemini mines. Two landmarks, the Bullion Beck headframe and the Shea building, were restored. The rest have been left in ruins.

All of the tests we conducted were put into numerical form and entered into a spreadsheet so that we could compare the results. We used an ALTA II reflectance spectrometer to measure reflected light at eleven wavelengths, including four infrared wavelengths. We also tested the pH of the samples using several methods, including universal test strips, a garden soil test kit, and a pH meter. We tested for lead using a sodium rhodizonate solution, which changes from orange-red to pink in the presence of lead in neutral soils and to green or blue in the presence of lead in acidic soils. Please see our previous post for details on these tests. Since the rhodizonate test was qualitative, we assigned numbers depending on the color of the final solution so that some comparison could be made.

For the samples, we selected ten areas inside the town of Eureka, including some where the soil has been replaced and others where the soil is original. We tried to pick areas that were representative of the town as a whole. At each site, we sampled the surface soil and soil about six inches below the surface. We also sampled 12 sites outside of town, including areas away from town as controls and areas on or near exposed mine dumps, such as those from the Tintic Standard, Swansea Consolidated, and Tesora mines. We also took samples from gullies or washes downstream from mining areas and dumps, and from an exposed ore body (which has not been mined or processed) at a road cut along U.S. Highway 6.

Test Results:

Chart 1: Comparing Different pH Tests of Soil Samples. The readings taken with our portable pH meter provide the most consistent results (and can be done easiest in the field).

As you can see from Chart 1 shown here, of the different methods we used to determine the soil pH, the pH meter was the most sensitive and consistently accurate. It was also easiest to use. It showed that most of the samples, were slightly acidic (between 6 and 7), but the samples taken from mine dumps and the areas immediately downstream were extremely acidic; in fact, some samples had a pH too low for our meter to read, which had a low limit of 2.5. Although not shown on this chart, the samples taken inside Eureka on our fourth collection trip all showed pHs near neutral (6 – 7).

Our lead test showed no discernable lead inside Eureka, even in soils that had not been replaced by the EPA. This is probably because our test is not sensitive enough for low lead levels. It becomes hard to distinguish the original color of the rhodizonate from the natural color of the soil unless there is enough lead present to create an obvious color change. In Chart 2, low levels of lead correspond very well with neutral pH soils.

Chart 2: Comparing Soil pH with Lead Levels. The lower the pH (more acidic) the soil samples were, the more lead was present with a correlation coefficient of rho = -0.876.

The most interesting result of our study was to compare pH with lead levels. Chart 2 shows that the highest lead levels were found on or immediately downstream from mine dumps, which correlated very well with low pH levels with a correlation coefficient of rho = -0.876. Mine dump soils had high lead content and were highly acidic. Of course, this doesn’t imply causality: the high acid doesn’t cause lead, and the high lead probably doesn’t cause the acidity, but if one is present, so is the other.

In Chart 3, the reflectance spectrometer tests were inconclusive as far as detecting a signature for lead. We compared the results shown with samples of pure lead, pure galena (lead sulfide), and silver-lead ore. There were no obvious wavelengths that gave a definitive fingerprint for only lead.

The one useful result of the spectrometer tests was to confirm the overall health of the soil samples; those with lower percent reflectance overall were darker, richer, more healthy soils with more plant life growing. The lighter soils had less plant life and higher overall reflectances. The soils at mine dumps were yellowish to light purplish due to the presence of sulfur compounds, and these also had no plant life, lower pH, and higher lead.

Chart 4: Comparing the Levels of Nitrogen, Phosphorus, and Potassium in Soil Samples. The nitrogen and phosphorus tests gave no predictable results, whereas the potassium test showed higher levels of potassium in mine dump soils with high lead content (rho = .687).

Chart 4 shows the tests we conducted on soil nutrients. The nitrogen and phosphorus tests were inconclusive, and are probably due to the poor quality of the garden test kit we used. The potash (potassium) test did show higher potassium in the mine dump soils where lead levels were also highest, although the correlation was only moderate (rho = 0.687).

Conclusions:

A visual inspection of the mine dumps outside of Eureka, Utah in the Tintic Mining District shows that the waste rock and soils are highly contaminated. No plants grow on the dumps or in the gullies immediately below them. They are stained a bright yellowish-orange, and soils in the nearby gullies have layers of red, yellow, and even green. Overall, they are lighter and less rich than nearby soils with plant life. Our tests show that these mine dump soils are acidic and have high levels of lead contamination.

Similar mine dumps were located at the west end of town (around the Gemini and Bullion Beck headframes) and south of town (Chief Consolidated and Eagle and Bluebell mines). If the same pattern of contamination occurred there as what we found in the Swansea, Tesora, and Tintic Standard dumps, then it is likely that the soils downstream in the residential areas of town were also contaminated by lead and sulfur compounds. We did not find evidence of this in our tests of original soils inside town, but our test was not sensitive enough to find the lowest levels of lead. Soil pH throughout the town was slightly acidic, which may indicate sulfur or even lead content. We were not able to get the data from the original EPA tests.

Soil discoloration in the wash west of the main Swansea mine dump at Silver City.

Both pH and potassium content appear to be well correlated with lead content, with pH having a particularly high negative correlation (-0.876). Perhaps pH can be used as a marker, since it is easily measured. Where lead is suspected, a pH reading showing high acidity would indicate a strong possibility of lead. It would be interesting to see if the two measurements decouple as one travels further downstream from the mine dumps along washes and gullies. Do the lead and the acid travel the same distances?

Soil layers showing different types of contamination, in the middle wash downstream from the Swansea mine dump.

Much remains to be tested. We have some additional grant funds that we will use to send four samples to an outside lab for detailed element analysis. I also hope to take all our samples to a local university and use an X-ray Fluorescence Spectrometer or Raman Spectrometer to get an accurate and precise readout of the lead levels and other heavy metal content. We need to determine the amount of sulfur compounds in the soils, and how that correlates with pH. We also need to pass our samples through a soil sieve and measure the relative sizes of particles and the amount of humus in each. We should test the mine dump soils to see if plants will grow in them compared to the other samples. Finally, we need to return to the site and collect more samples of other mine dumps, as well as the soils around and downstream from the dumps we’ve already tested. We need to determine how far the lead contamination and acidity travel down the washes and gullies and the extent to which the slope of the land affects this.

As with any field research study, it’s hard to keep all the variables constant. We’ve been careful and consistent with our tests, recording each location and using controlled testing conditions in the lab. But there are factors we can’t control. It could be that the low plant life on the dumps is simply because this is a desert, and plant life takes time to get established after soils are disturbed. The dumps were all dug up and the best materials were transferred to a leaching pile nearby in the 1980s. 30 years is not enough time for climax vegetation of sagebrush and juniper trees, but is enough time for grasses and low brush to grow. In general, soils in the area are poor in nutrients except where higher levels of water (such as in washes or gullies) allow more plants to grow and decay into better humus.

Staining on the asphalt where water draining off of the Swansea mine dump runs over the road near Silver City.

During our Intersession period between third and fourth terms, I taught a class that would help complete our study of lead contamination in the Tintic Mining District around Eureka, Utah for our American Chemical Society Hach grant. We had already visited the area three times to collect samples in the various mine dumps around the area, but we needed one more trip to collect samples from inside the town of Eureka itself. We traveled down for this last trip on Thursday, March 14, 2013. I had three students with me from Walden School: Jeffrey, Indie, and Aaron.

Aaron, Jeffrey, and Indie collecting samples of a hydrothermal vein at a road cut on Highway 6.

We had scoped out the town and decided to collect at ten locations in the town and at least one location further southwest outside the entire district as controls. The town was cleaned up by the EPA as a superfund project, and $26 million was spent to dig up contaminated topsoil in sensitive areas, such as playgrounds, the baseball field, and lawns at the high school. Other areas have been covered with limestone fragments, or rip-rap, dug up at a quarry about five miles outside town and supposedly beyond the contaminated zone. Still other areas in town have had plastic netting laid over the ground, supposedly to prevent erosion from washing contamination back into the town. And there are many areas that have not been touched, with climax vegetation (mostly sagebrush and some juniper trees) that would take decades to grow. These untouched areas are even found upslope from sensitive areas, such as the high school. There doesn’t seem to be much rhyme or reason to it. The EPA claims that the problem has been solved, but my goal with this study is to provide independent evidence. Are areas inside the town still contaminated?

Headframes at the Eagle and Bluebell Mines

We had hoped that students at Tintic High School would identify and collect samples inside town, but the teacher that was going to collaborate with us bowed out because it was getting too close to the end of the year and he needed the time to prepare his students for state mandated tests. So instead, my students and I had traveled around town on our previous trips looking for candidate locations that will give us a good cross section and not cause problems with identifiable private property

Collecting samples near the High School

I also wanted to get soils from a typical mineralized area that had not been mined or processed. There are a series of road cuts leading into town from the east where U.S. Highway 6 goes around several sharp turns. One of these curves cuts through a section of reddish-yellow rock and soil, the marker of a hydrothermal vein. We stopped and collected two samples, one from yellowish soil and one purplish-white. Then we drove on in to town to start collecting samples there.

We began by driving up to a dirt parking lot near the high school baseball diamond. There is an ATV track there where contamination is likely to have been stirred up by the four-wheelers and washed down a small gully through climax sagebrush and junipers. We collected inside the track, in the gully itself, and at the base of the junipers in what was undisturbed original soil.

A pump used to drain water from the mines. Power for the pump came from the Nunn brothers’ hydroelectric station in Provo Canyon.

We then proceeded around town, taking samples on the surface and about six inches below at several locations, including a few empty lots, spots next to road right of ways and the city park, downslope from the Eagle and Bluebell mine dumps, and around an old house foundation that was long since abandoned and crumbling into ruin. Altogether we collected at ten sites, or twenty samples, in town. We then drove out of town to the west and collected samples from the bottom of a wash about half way down to the old CCC camp. This would be a control.

Map of Eureka, Utah

Although we needed to collect quite a few samples in a short period of time, we also took some time to explore more of the town. Around the museum, I explained to the students how the equipment worked, such as the pneumatic hammers, skip cages, water buckets, and muckers. They looked around the old jail and discovered some papers in a room underneath, including a booklet summarizing clean-up efforts after the flooding in 1983. We also found an old, yellowed map of Eureka itself. I carefully took photos of these documents and put them back where we found them. It was a sunny, warm day and we didn’t need coats even though there was still snow on the ground in places. We drove up to get some pictures of the Eagle and Bluebell mine sites. I got out of the car and walked along a hill that is covered in rip-rap to take photos of some old mine equipment and got myself stuck in a snowbank for a minute.

Mining gear at the Chief Consolidated Mining Company headquarters.

All told, we have about 42 samples from over 20 locations all over the district. We had identified these areas using Google Earth last fall. In addition to our sample collecting, we shot video and took photos as we traveled around town, with the intent to put all of this into a video on the history and current challenges of the town. Now for the analyses!

Plastic netting used by the EPA to slow down erosion on slopes, allowing native plants to grow.

Ruined foundation of a house in Eureka. We sampled near here, since yard fill was often collected from the mine dumps.

On Tuesday, March 12, 2013 I took three students down to Eureka, Utah to collect our third set of soil samples for our Amercian Chemical Society grant project. Jeffrey, Sean, and Indie helped to collect samples and measure the soil pHs, as well as explore the history of the Tintic Mining District.

Mine dump with contaminated soils at the Tintic Standard Mine

This time our first stop was at the old Tintic Standard Mine workings above Burgen and Dividend in the East Tintic District. Of all the ore bodies in the area, these on the east side of the Tintic Mountains were the last discovered and the Tintic Standard Mine was in full production by the 1920s. A reduction mill was built across Goshen Valley at the warm springs near Genola. Workers lived in a company town below the mine called Dividend. The mine produced well into the early 1940s, when it was partly shut down for the war effort, then re-opened. Work continued sporadically into the early 1970s.

Collar and shaft at the Tintic Standard Mine. Even with a chain link fence around the hole, the loose soil at the collar could cave in and makes this shaft a dangerous place if you get too close.

There are still quite a few artifacts and ruins at the site, and care must be taken as there is a large vertical shaft with loose dirt around the collar, so you should stay well back from it. There is a large glory hole on the back hill and two water tanks further up, with the remains of a wooden ditch that brought water down to the company buildings and change room. The main portal to the mine went back from the change room, where there is still an old stove to keep the miners warm. That portal has been sealed off.

Stove in the change room at the main portal of the Tintic Standard Mine. This portal was active off and on into the 1970s.

After exploring around, we collected some samples from the mine dump at the bottom of the hill where melting snow had created a clayey puddle. We also collected several samples along a trench that had been cut into the waste rock dump, where the soil was discolored with purplish or yellow deposits. The pH indicator needle pegged several times, showing an acidic pH of less than 3.5. It will be interesting to see what kind of lead content these samples have.

Jeffrey and Indie taking samples at the Tintic Standard Mine

We then drove into Eureka and scouted around town for some additional sample sites to collect on our final trip on Thursday, as well as to look around the mining museum, old City Hall building with its jail in back, and the cemetery. I showed the students how miners worked the air-driven hammers and how water was sprayed into the holes through the center of the drill steel. We looked at the skips or man cages, the water removal buckets, and the mucker machine out front. We walked around Main Street, which was very quiet for a Tuesday afternoon. Only a few cars were driving through.

David Black by City Hall on Main Street in Eureka, Utah.

Water chute, tanks, and old foundation at the Tintic Standard Mine

We drove out through the west end of town on Highway 6 and took a detour through the cemetery, recording with the Flip cameras as we went. We explored around the town of Mammoth and collected samples in a wash at the mouth of Mammoth Canyon. We then went on around to the Swansea mine dumps at Silver City to continue collecting samples.

Ruins of the old power plant in Eureka. Heavy machinery moving through town has contributed to the deterioration of historic buildings like this one.

Since last week, the snow has mostly melted and the ground dried out to where we could walk on it in most places without leaving muddy footprints. We sampled in several washes running off the main dump and in soils between the washes where some scrub brush survives. The main wash feeding off of the dump had several layers of brightly colored soils, ranging from reds to yellows to even a shade of green.

Mammoth Mine, headframe, and glory hole. This was the deepest mine in the district, with the richest concentration of silver and gold ore.

I can see we need to do more studying here, to see how much lead and acidic runoff continue down these washes into the valley beyond. The runoff water has left a red stain on the asphalt of the road over a hundred yards from the main dump. The soil on and near the dump itself and in the bottom of the washes is devoid of life. Even though the last time this mine waste was dug up was the 1980s, when the leach pile nearby was created, no plant life has yet to colonize the contaminated soils in about 30 years.

Sean and Indie at the Silver City mine dump.

David Black taking pH readings in the middle wash draining the mine dump at Silver City.

All told we had an enjoyable and low-key trip, and even though it was overcast the day was fairly warm. We had now collected all the samples we needed outside the remediated zone.

Science Research Class at Walden School on our second collection trip.

After our fall semester, my research science class ended and the two sections of chemistry were consolidated down to one, with me teaching a computer technology course third period instead of chemistry. Without the two classes that could support the Tintic soil analysis project, I had to put the project on hold until I could get some more students involved. We also had an unusually cold January and February, with snow staying on the ground. This hampered our ability to collect samples. Between 3rd and 4th terms we hold a two-week Intersession at Walden School of Liberal Arts that allows us to teach specialty courses, and I dedicated my course entirely to finishing the Tintic project.

Altogether five students took the course, including Jeffery, Indi, Sean, Jem, and Aaron. To finish collecting all the samples, we had to take three additional trips down to the Eureka area. We were fortunate that the weather cooperated and warmed up enough that the snow melted.

Our second collection trip was on March 5 to the area of the Knight Smelter, the cyanide leeching pile, and Silver City. We stopped at the Bullion Beck Headframe on the way to take a group shot.

Ruins of the Knight Smelter built by Jessie Knight to process silver ore.

The Knight Smelter was built by silver tycoon Jesse Knight, who made his initial fortune with the Humbug Mine, then expanded along the Iron Blossom lode. Eventually, Uncle Jesse needed a smelter to concentrate and refine the ores from his mines, and he built it south of Eureka near the Union Pacific line. To connect his mines with the smelter and the Union Pacific main line, he built a narrow gauge railroad so that the smaller engines could make the turns and the steeper grades. A fairly level grade was built around the hills into his mines, and the road I walked on to the Iron Blossom #2 last fall followed this old grade. Jesse Knight contributed quite a bit of money to what was then the fledgling Brigham Young Academy, now Brigham Young University. The Jesse Knight Building, where I had several classes, is named after him.

Tank foundations and kiln at the Knight Smelter

The technology for refining ore went through rapid change in the 1920s. The smelter only operated for about four years, at which point it became cheaper to ship the ore by rail to the more modern smelters in Murray. The same thing happened with the Tintic Standard Mine and the reduction mill near Goshen.

There isn’t much left of the Knight Smelter except crumbling foundations for the solution tanks, a few archways where the kilns stood, and a pile of slag. Just to the south is the leeching pile. During the 1980s the price of gold jumped up when we went off the gold standard and the price was allowed to rise. Investing gurus such as Warren Buffet were advising people to invest in gold, and that drove up the price even more. Now, all these old tailings and waste rock piles that hadn’t been economical to process suddenly were. A layer of thick plastic was laid down and the waste rock crushed and piled onto the plastic, then a solution of cyanide was pumped over the pile. The cyanide would chelate with the gold and silver and trickle down through the pile into its lowest area, where it was pumped out and transported for smelting. This same process is being used at the Cripple Creek and Victor gold mine in Colorado.

Collecting a sample inside the kiln at Knight Smelter

We walked into the old smelter ruins and identified spots where there would likely be contamination, such as inside the kiln and underneath the tanks. We saw that a layer of sand was laid down under the tanks over the original soil, which is now covered with new soil deposited since the 1920s. We also collected samples from the top of the leeching pile. I picked up some samples of slag as well.

This smelter took the original ore and concentrated it by crushing and chemical action, using both physical and chemical separations. Mercury was used to bind to the silver (amalgamation). The amalgam was then heated up in a kiln to drive off the mercury and leave silver and gold. Since the silver started out in a compound with a higher oxidation state (+1) and was now a metal with an oxidation state of 0, this process is also called reduction. There were several reduction mills in the Tintic District. The leftover ore, after heating, still contained appreciable amounts of iron and lead, and was dumped onto a heap in a molten state. This waste material is called slag.

Slag at the Knight Smelter.

Sample under the tank foundations. Notice the layering of the soil; a layer of sand was laid down under the tanks when they were first built which is now covered with new topsoil.

We moved on to the waste rock pile at Silver City where the Swansea Consolidated mine was located. Here, water runoff since the pile was created in the 1980s has washed small gullies fanning out south of the pile, crossing the road, and going on down the valley. The asphalt on the road is stained red with the iron sulfides. We collected on the pile itself, and used a portable pH meter to test the soil at locations on and near the pile. It was still too muddy to walk around much, and we were getting short on time, so we packed back up and drove back to Provo. We collected ten samples from five sites on this trip.

Testing the soil around the Swansea mine dump. The pH is very low, under 3.0.

It’s time to take a break from recounting my tour through Colorado’s mining towns last summer and catch you up on what we’ve been doing this year at Walden School of Liberal Arts.

Maples in the fall near Eureka, Utah – with junipers and rabbit brush.

As mentioned earlier, we received a grant from the American Chemical Society to study lead contamination in the soils in Eureka, Utah and the surrounding area. The grant provided funds for travel, equipment, chemicals, and supplies. It took until early October to receive the money, so our first trip down had to wait until mid-October. It meant we wouldn’t have much daylight, but we’d have to do our best.

Canyon of Fire: Maples in the East Tintic Mountains

I’ve been gradually documenting the history of the area, collecting historical photos, taking photos around the town myself, etc. Back in 2009, I took a group of students with me to interview June McNulty, President of the Tintic Historical Society. He showed us through the museum and we videotaped the tour. Now, with this grant, we can tell the story of recent events in Eureka, especially the history of the EPA superfund project over the last ten years that cleaned up or covered up contaminated soils in the town.

TIntic HIgh School from the Godiva Mine site

My science research class researched the history of the area during first term while we were waiting for the grant funds. They identified 20 collection sites outside town using GoogleEarth. Some of these are old mine waste dumps, some are around smelter or concentration plants or leeching piles. Others are control sites outside the district. We were going to collaborate with students at Tintic High School, who were to collect from sites in town. Unfortunately, our collaboration fell through, so my students eventually collected from sites inside the town as well.

Valley of maple trees from a mine dump in the East Tintic Mountains

In preparation for our sample collection trips, I traveled down to the area to get some photos of fall foliage on Saturday, Sept. 22. I got there just at the right time, when the maples in the canyons were at their brightest. I photographed some areas along Highway 6 leading into town and filmed the maples in the canyons along the road leading over the top to Dividend. I then took videos around town by attaching a Flip camera to my left rearview mirror with a small claw-style tripod. I drove up to the Godiva mine site and took photos down toward the high school, then drove further up the canyon past the Knightsville site and hiked around some mine dumps further up. I had seen that there was a valley nestled inside the East Tintic Mountains from GoogleEarth and my 3D models of the area. There was a road leading along the edge of the hills, and I walked around as far as the site of the Iron Blossom #2 mine. The headframe there has recently collapsed. It was a nice trip and the photos turned out well. I also saw and photographed several deer.

Doe a Deer: A mule deer doe in the East Tintic Mountains

Ruins of the Irom Blossom #2 Headframe

I took four students to the area on Oct. 19 and we collected samples and explored the area, including the road over Silver Pass. We first collected from some old evaporation ponds near Elberta where hot water pumped out from the Burgin mines was allowed to cool and settle before discharging it into Utah Lake. During the early 1980s, as I drove home from college to my hometown of Deseret, I would pass through this area and see the water steaming as it passed down the gulley to the ponds. This was the last time they had attempted to open the mines at Burgin. We sampled from two locations inside the old ponds, which can be reached by a short walk from Highway 6.

Collecting samples at the settling ponds near Elberta

We then collected from the bottom of the wash at the mouth of the canyon leading up to Burgin. The soil here looked healthy and contained a combination of sand and humus. We then stopped at the old Burgin concentrator and took some pictures. I talked with the men at the main office of the Chief Consolidated Mine operations there about getting some samples from the tailings piles (they corrected me when I mentioned “tailings piles” around the headframes themselves and said those rocks were more properly called mine dumps or waste rock; tailings are the actual ore that has been processed).

Silver ore concentration plant at the Burgin mine

We took photos around the Trixie headframe, then drove on up the canyon over the top of Silver Pass, which I had not done before. This was the opening of the deer hunt, so I didn’t want to venture too far from the road without orange clothing.

Headframe at the Trixie Mine above Burgin.

We also collected at a mine dump next to the road in Ruby Hollow, which I later identified as the Tesora Mine. The soil there had a bright yellow color and contained obvious sulfides. Part of the shaft is still there without much protection around it.

Collecting samples at the Tesora Mine dump in Ruby Gulch

I also showed the students Silver City, the leeching pile from the 1980s when much of the waste rock and tailings were heaped up and cyanide solution was sprayed onto it, chelating the silver and gold out of the rocks. We stopped at the Bullion Beck headframe for photos and walked around the Tintic Mining Museum. It was late afternoon by then and time to get the students back.

Waste rock pile at the Swansea Consolidated Mine near Silver City

Altogether we collected six samples from three sites and the students had a chance to get to know the area. I knew that we would have to be more productive on our next trips. Back at school, we did some simple pH tests and found the first two sites (Elberta Ponds and Burgin Wash) were near neutral pH, but the Tesora Mine samples were quite acidic, at a pH of about 3.5. Other tests would have to wait until we ordered the testing supplies.

For the last week, I’ve been busy preparing for my classes at Walden School, including inventorying the science lab room (which is also my classroom) and planning out my course schedules. I’ll be teaching two sections of Chemistry, one of Astronomy, one of Computer Technology (a basic computer literacy course required in Utah), a section of Media Design, and a section of Video Production. This is, for me, a perfect schedule. In the meantime I’ve also been preparing a series of maps and 3D images of the Tintic Mining District, focusing on the ore deposits and the various mines located there. I’ve also prepared the script for this section of the video, which I have pasted below:

MInes and Roads in the East Tintic Mtns.

Tintic Geology

To understand how the ore bodies in the Tintic District were deposited, we have to start about 800 million years ago in the Precambrian Period when the western portion of the North American craton rifted away from the rest of the continent along a line where the Wasatch Front now lies – this Wasatch Line has been an important hinge line in Utah’s geology ever since. For the next 600 million years, a sequence of ocean sediments including dolomite, limestone, shale, and sandstone were deposited off the coast in the geosyncline that would become western Utah. Beginning 150 million years ago, Nevada and then western Utah were uplifted as the Farallon tectonic plate was pushed under North America. Like a throw rug being wrinkled up as it’s pushed over a hardwood floor, western Utah was folded by thrust faults into a large mountain range during the Sevier orogeny about 70 million years ago. This thrusting continued across eastern Utah and into Colorado and Wyoming during the Laramide orogeny, building up the Uintah and Rocky Mountains.

Mines in the eastern portion of the Tintic Mining District

Then, about 50 million years ago, the Farallon plate began to collapse from underneath the continent. As it peeled away, a wave of volcanism moved from east to west across Colorado and Utah. Intrusive laccoliths rose to the surface, bulging up the LaSal and Henry Mountains in eastern Utah and forming explosive calderas in several places in western Utah. About 35 million years ago, a series of calderas formed in the area that would become the Tintic Mountains. A large andesitic volcano rose up from eruptions of ash and tuft.

Ore samples from the Tintic Standard Mine, eastern district.

About 31.5 million years ago, the volcano collapsed as the intrusive magma began to cool. Mineral rich fluids were injected into the surrounding limestone, quartzite, and dolomite as replacement beds. The hot magma caused the carbonate rocks to decompose; for example, limestone turns into lime or calcium oxide and carbon dioxide gas when heated. This left large cavities that then filled up with the mineral-laden magmas. These deposits are called stopes, such as the famous Oklahoma stope of the Chief Consolidated mine. The carbon dioxide released from the decomposing limestone and dolomite in turn dissolved into the hot magma, making it a kind of lava champagne, and reacting with it to form various exotic minerals, some of which are found nowhere else.

More ore samples from the Tintic District

The primary ore-bearing minerals in the Tintic District are enargite, tetrahedrite, galena, sphalerite, pyrite, marcasite, and native gold, silver, and copper. But many more minerals are present, including unusual minerals that blend copper, silver, tellurium, arsenic, sulfur, carbonates, hydrodixes, etc. At the Centennial Eureka mine, over 85 different minerals have been identified, ranging from common pyrite, malachite, and azurite to minerals found only here. It is the type locality (where the mineral was first identified) for leisingite, frankhawthorneite, jensenite, juabite, utahite, and eurekadumpite. Other rare minerals include xocomecatlite, carmenite, adamite, duftite, and mcalpineite.

These mineral deposits occurred around the edges of the caldera and formed the five large ore zones of the main Tintic District. The Gemini Ore Zone runs to the west of Eureka south to the north edge of Mammoth Gulch. The Gemini, the Bullion Beck and Champion, the Eureka Hill, and the Centennial Eureka mines (known collectively as the Big Four) are located on this zone.

The Chief-Mammoth Ore Zone begins under the center of Eureka and extends due south across the mountain to the east end of Mammoth Gulch. The Chief Consolidated mine is located on the richest ore body, which is right under the center of Eureka city; up the hill is the Eagle and Blue Bell mine, named for the beautiful deposits of azurite found inside. Further south over the top of Eureka Peak lie the Grand Central, Mammoth, Apex, and Gold Chain mines that are also part of this deposit.

Ore Zones and Major Mines of the Tintic Mining District

The Plutus Zone branches off of the Chief-Mammoth Zone high up in the Tintic Mountains. The Godiva Zone starts just east of Eureka and runs southeast in a curve where it joins the Iron Blossom Zone, which continues in a curve south and then southwest. Some mines in these zones include the Godiva, May Day, Humbug, Beck Tunnel, Sioux, and Iron Blossom mines.

In the eastern section of the Tintic District, several zones of minerals were deposited and were among the last to be discovered because they are overlain by 400 feet of igneous rock. These bodies include the Burgin ore body, the Tintic Standard, and the North Lily bodies. Other bodies are located at the Apex and Trixie mines.

In the southern section of the Tintic District, the large replacement bodies give way to smaller fissure veins that are only two feet wide on average but can be up to 4000 feet long. Here, the mineral-bearing magma was injected into cracks and fault lines already existing in the host rocks. The Dragon mine is the only true open pit mine in the area; it sits on top of a network of fissure veins at the south end of the Iron Blossom Zone. Other mines in the area include the Swansea and Sunbeam mines at Silver City, the Tesora and Treasure Hill mines at Ruby Gulch, and the Showers mine at Diamond Gulch.

More ore samples from the Tintic Standard Mine

The final chapter in the area’s geomorphology began about 17 million years ago when normal faulting created the Basin and Range province, lifting up blocks to form the mountain ranges of Utah and Nevada, including the East Tintic Mountains. Other blocks sank to form the valleys, such as the Tintic Valley. Erosion has exposed the ore bodies in many places, including the outcropping that George Rust stumbled over in 1869. It was to become the Sunbeam Mine.

On my visit to the area around Eureka, Utah last Friday, June 4, I not only wanted to visit Mammoth and Silver City, but to also document the efforts by the Environmental Protection Agency to clean up the town. I had traveled through Eureka a few days before on Memorial Day and noticed that the lawn and soil around the LDS chapel in Eureka was being dug up to a depth of about 18 inches. On Friday, crews were in the process of bringing in new soil in dump trucks and spreading it over a layer of black plastic where the lawns used to be. Normally I wouldn’t have noticed it much – just chalked it up to them putting in a new sprinkler system or something similar. But I knew differently. This was the latest site in an ongoing process to replace the topsoil throughout the entire town, which is a huge undertaking. All the old mine sites throughout the district have left a legacy of environmental contamination and pose a danger to careless explorers who try to enter mine shafts or tunnels or ruins.

Ore dump at Dividend, Utah

When silver ore was discovered in the East Tintic Mountains by George Rush in 1869, it ignited a stampede of mining claims that spread throughout these mountains. New deposits were soon located and claimed, and the ore was assayed to be rich in silver, gold, lead, zinc, copper, and other minerals, usually in the form of metal sulfides. The most level sites near the mines quickly grew into the towns of Eureka, Mammoth, Silver City, Diamond, Knightsville, Dividend, etc. These towns were usually as close to the mines as possible so the miners didn’t have far to walk, so that miner’s houses and the mine buildings, hoists, smelters, railroad depots, and city businesses all competed for space in the narrow canyons. Tailings dumps of discarded minerals and slag from the smelters covered the hillsides around and above the town. Dust from these piles was blown by the frequent winds (this is western Utah, after all) and blanketed the whole town. Nobody thought much of it at the time. It was all just part of life in a mining town. But the entire topsoil was contaminated with lead and other metals down to about two feet under the surface.

Limestone rip-rap covering a slope in Eureka, Utah

Clean-up operations near downtown Eureka, Utah

Today, the EPA has identified the area around Eureka as a SuperFund site, spending millions of federal dollars to clean up the contamination. One by one, the yards of the residents and businesses are being dug up and the soil replaced, brought in from a staging area east of town. To prevent the tailings piles from blowing more toxic dust around the town, broken limestone rocks called rip-rap are being hauled in from a nearby quarry and are carefully placed to cover over the tailings piles to prevent further erosion by wind and water.

Mine dump in East Tintic Mtns.

The work is progressing throughout Eureka, but the entire mining district has the same problem. Recent exploratory work has dug up the tailings piles in Silver City again, leaving the yellowish sulfides once again exposed to erosion. Many of the mine sites in the hills are owned by small-time private owners who keep the mines open on an occasional basis. They don’t have the resources to prevent the erosion of their tailings piles, and much of the East Tintic Mountains is contaminated just as Eureka itself is.

Abandoned mine shaft at Dividend, Utah

Another problem in the area is the many abandoned mine tunnels and shafts. Mines today are required to provide reclamation funds before the mine can even open, but it wasn’t an issue in the 1800s and early 1900s when most of these mines were active. The owners took the ore from the hills, then left all the scars, holes, pits, slag, tailings, and buildings behind when the ore ran out and their companies closed. Now these ruins are a hazard to casual explorers; every year or two someone dies falling down an abandoned mine shaft in Utah. The state has begun a program to close off these mines; to place grates or metal doors in the tunnels and shafts or to blast the entrances closed. Over 8000 mine sites have been closed off throughout the state through this program, but many, many more remain to be done.

Ruins of the Knight Smelter at Silver City, Utah

Smelting or concentrating the ore brought its own environmental problems. Jesse Knight, the silver magnate that started Knightsville just southeast of Eureka, also built a smelter at Silver City in the early 1900s that operated for about eight years. The foundations of this smelter still remain, as do residual chemicals used to concentrate the ore, including mercury. When I visited the site on Friday, I found a man and his two young girls exploring the site. I suggested that he wash off his girls’ hands and shoes carefully once they were done because the whole site is contaminated with mercury (June McNulty, who runs the Tintic Mining Museum in Eureka, told me that he used to play with pools of liquid mercury metal that would seep into pockets around the smelter).

Remains of the Knight Smelter at Silver City, Utah

Right to the south of the old smelter lies a large heap of grayish tailings, now slowing growing a crown of weeds and grass. All the tailings left from the Knight mill were scooped up in the 1980s and placed on a pad with drainage pipes running through the pile, then a solution of cyanide was pumped and sprayed over the pile, leaching its way down through the tailings and chelating with the remaining gold and silver. The ore from these mines has been worked and reworked to get every last fraction of value out of it. But now the pile has been left just like all the other piles around, but with the addition of cyanide. I don’t know if steps have been taken to reclaim the pile, but I wouldn’t want to walk around on it.

Cyanide leaching pile at Silver City, Utah

The efforts to clean up these environmental messes is necessary, but it does come at a cost beyond just money. To clean up the town and make it safe to live in, its essential history and character has been changed. The heavy equipment moving in limestone and soil has shaken apart a number of fragile historical structures, including buildings, homes, and headframes. Where there were colorful tailings piles slowly returning to nature, there are now carefully constructed fresh piles of gray limestone rocks, an ideal hideout and breeding ground for rattlesnakes (no joke here – I ran over one in my minivan as I was driving up the road to Mammoth). Eureka doesn’t look the same as it did ten years ago.

One can argue that Eureka must be dynamic and capable of changing. It’s not a museum but a living town, and change is part of life. But the historian in me hates to see history destroyed in the process. That is one of the main reasons I’ve started the Elements Unearthed Project and have traveled to Eureka several times in the last few years with my cameras and equipment; as the EPA clean up progresses, the town is changing and I want to preserve what can be preserved of the history before it’s gone forever.

Erosion of tailings piles at Silver City, Utah

The beryllium video second half is progressing well. I’ve decided to do the three episodes on the TIntic Mining Districts next instead of blown glass because It’s fresh on my mind and I now have all the footage and photos I’ll need. My goal is to get the beryllium video done and uploaded by the end of this week, then the Tintic videos by mid-July. Then I’ll start hitting the streets looking for financial sponsorship to continue this project.